Grid template positioning in interventional medicine

Abstract

A processing device (1) and method for determining a position and / or orientation of a multi-hole grid template in a medical intervention procedure are disclosed. An anatomical space information processing unit (2) receives and / or processes data representing a target spatial volume in a body, and a grid position sampler (4) generates candidate positions of the grid template. A quality calculator (5) calculates for each candidate a quality measure indicative of a fitness of the candidate position of the grid template for the intervention procedure. A position selector (6) selects a position and / or orientation from the candidates based on the quality measures. For each candidate, a spatial relationship between each grid hole trajectory and the target volume is determined, and the quality measure takes at least this spatial relationship into account.

Description

Technical Field

[0001] This invention relates to the field of interventional procedure planning, such as brachytherapy and ablation procedures. Specifically, this invention relates to apparatus and methods for procedure planning, wherein a grid or template is used to support and guide interventional tools, such as needles, catheters, etc., to be inserted into the anatomical volume of interest through selected holes in the grid. Background Technology

[0002] In focal therapy, one or more focal sources are used near and / or within a treatment volume (e.g., a cancerous lesion) within the body. Such focal sources can be concentrated in or located by an interventional focal therapy delivery device such as a needle or catheter. Focal sources can provide highly localized energy exposure to damage cells within the treatment volume while protecting healthy tissue outside that volume. Generally, but not strictly limited to this, focal sources can deposit energy according to the inverse square law to achieve this advantageous highly focused (localized) therapeutic effect. Many forms of focal therapy exist in the art. Perhaps the most well-known form is brachytherapy, which involves placing one or more radioactive seeds (sealed radioactive isotopes) in or near the area requiring treatment. Other examples include thermal ablation, microwave ablation, ultrasound ablation, radiofrequency ablation, photothermal therapy, laser therapy, etc. Specific sensitizing techniques, such as those used in photodynamic therapy, can also be employed. While cryoablation, strictly speaking, does not rely on a focal energy source but uses a focal heat sink, it can be considered entirely similar and thus an example of another form of focal therapy.

[0003] It is known in the art to use rigid or flexible grid templates positioned on the patient's body to guide and support treatment delivery devices for lesions such as needles.

[0004] For example, in prostate brachytherapy, a needle or catheter can be inserted into the prostate and / or surrounding tissues through an alignment template positioned in the perineum. The template thus guides, supports, and (temporarily) fixes the needle or catheter, enabling it to reach (multiple) intended delivery sites within the body with good positional accuracy, and allowing (multiple) treatment instruments to remain in their intended positions for the predetermined required time during the procedure.

[0005] While this disclosure is intended to provide means and methods for planning and performing precise positioning of such a grid template relative to the body and a predetermined volume therein, which is particularly useful for the treatment of lesions, embodiments are not necessarily limited thereto. Other interventional procedures that may use the grid template to insert tools into precise locations within body tissues may also benefit from the invention, such as biopsies.

[0006] Typically, medical imaging techniques can be used to identify and segment regions of interest in the body, such as the primary treatment volume and nearby organs that may pose a risk. This information can then be used to perform manual forward planning or automated backward planning to find a set of delivery parameters, which may include, for example, the selection of catheter or needle positions on a grid template, their insertion depth, dwell (or ablation) time, and / or treatment power parameters (e.g., radioisotope flow rate or ablation power). For example, in brachytherapy backward planning methods, grid aperture trajectories intersecting the lesion region to be treated can define the target lesion intersection segment for sampling a set of dwell positions where the radiation source can remain for a given optimal time. In typical planning, multiple such available trajectories can be selected and used in a sequential treatment mode, for example, inserting the brachytherapy radiation source (or ablation tool) through each selected aperture based on determined parameters, such as determined dwell time and insertion depth.

[0007] However, the plan is constrained by the positioning of the grid template, which typically includes multiple through-holes (e.g., arranged in a grid pattern) that define the available positions of the conveying equipment on the predefined grid, for example, along paths through these holes and perpendicular to the grid template.

[0008] For example, for very small lesions, suboptimal grid placement may limit the maximum treatment planning quality achievable under planning constraints. In the worst case, very small lesions may lie entirely between grid aperture tracks. Therefore, optimal treatment within these constraints could increase the number of lesion treatment sources to surround the lesion as much as possible, while increasing undesirable damage to surrounding presumed healthy tissue, such as the increased risk of adverse side effects. Unfortunately, this situation is not uncommon in clinical practice. For example, clinicians may include a margin around the overall tumor volume (e.g., 1-2 cm) to expand the target volume and obtain some intersecting grid tracks. In this case, without considering the margin, no tracks are available for optimization, and therefore no suitable brachytherapy source or ablation station location. However, this margin also means that healthy tissue near the overall tumor may be affected, such as being destroyed by treatment, which could lead to potential side effects.

[0009] However, this method also has its advantages. By restricting possible needle positions to a predetermined grid, the complexity of the planning algorithm is reduced, for example, it can remain tractable. For instance, since the needle positions are restricted to potentially large but finite (discrete) numbers, direct search and / or integer programming planning strategies can be used. Similarly, due to the finite size of brachytherapy seeds or ablation tools, the number of dwell positions (i.e., with substantially different effects) can also be constrained to discrete numbers. While robotic systems are known in the art that allow interventional tools to be positioned substantially continuously relative to a predetermined coordinate system, template-based methods still offer advantageous cost-effectiveness, simplicity, and speed, which may be preferred in many cases.

[0010] Document WO2016 / 059603 A1 discloses an interventional therapy system comprising at least one catheter configured to be inserted into an object of interest; and at least one controller which: acquires a reference image dataset comprising multiple image slices forming a three-dimensional image of the object of interest; defines a restricted region within the reference image dataset; determines positional constraints of the at least one catheter based on at least one of a planned catheter crossing, the peripheral boundary of the object of interest, and the restricted region defined in the reference dataset; determines at least one of the position and orientation of the distal end of the at least one catheter; and / or determines a planned trajectory of the at least one catheter based on at least one determined position and orientation of the at least one catheter and the positional constraints.

[0011] EP1374949 describes an illustrative method for brachytherapy planning. This reference discloses a real-time radiotherapy planning system. A three-dimensional image segmentation algorithm is used to identify specific organs within an anatomical region of interest. A treatment plan for implementing radiotherapy is then determined, defining the number and location of hollow needles within the anatomical region and the radiation dose to be delivered. A genetic optimization algorithm based on single- or multi-target anatomy is used to determine in real-time the optimal number and location of the hollow needles(s), the location of the energy source in each hollow needle, and the dwell time of the energy source at each location. The needles(s) are then inserted into the anatomical region under the guidance of a template or guide tool, and the energy source is delivered through the hollow needles. Furthermore, for post-planning purposes, the realized needle locations and dwell times can be determined based on three-dimensional image information. Specific embodiments described in this disclosure relate to a perforated motorized template that uses a single guide tube through which needles can be inserted. This guide tube can be positioned at each location in a virtual template grid such that the positioning of the needle relative to the template is not limited by a physical grid of holes. Therefore, the virtual grid configuration is limited to the diameter of the needles used. Summary of the Invention

[0012] The purpose of this invention is to provide simple, effective, efficient and / or good means and / or methods for determining the position and / or orientation of a grid template, for example on or near the patient's body surface, for supporting and guiding interventional tools (such as needles, catheters, etc.) to be inserted into the anatomical volume of interest through the grid openings during interventional procedures such as brachytherapy or ablation.

[0013] The apparatus and method according to embodiments of the present invention achieve the above objectives.

[0014] An advantage of embodiments of the present invention is that, when the grid is placed in its defined location, the grid position is optimized to provide good accessibility (e.g., good physical proximity and / or coverage) to the treatment volume of interest in the body through the delivery path (for needles, catheters or other interventional tools) via the grid apertures of the grid.

[0015] The advantage of this invention is that the delivery path through the grid apertures can be optimized to intersect with the treatment volume of interest as much as possible.

[0016] The advantages of this invention are that it can achieve good therapeutic effects through procedures such as ablation or brachytherapy, for example, in the treatment of unresectable tumors. Another advantage is that it can reduce or avoid adverse side effects, such as avoiding or minimizing damage to healthy tissues.

[0017] Another advantage is that the treatment dose (e.g., radiation dose, ablation energy) can be reduced by being able to deliver the dose precisely within the treatment volume. Another advantage is that good patient recovery after treatment can be achieved (e.g., rapid, without adverse side effects). For example, to minimize unnecessary damage to nearby healthy tissue, the total delivered radiation dose or thermal ablation zone should be as consistent as possible with the tumor contour (potentially including a margin around the tumor deemed appropriate by the clinician and as minimally affected as possible by constraints imposed by the grid).

[0018] The advantages of embodiments of the present invention are that the currently disclosed method can be applied to a wide variety of interventional procedures, in which it is advantageous to precisely locate interventional tools(s) within a volume of interest in the body via a delivery path defined by a template grid. For example, the method can be applied without requiring knowledge of the specific procedure being applied, e.g., only considering the purpose of providing good access to a predetermined volume of interest in the body via the delivery path provided by the template grid, preferably sampling as many locations as possible across the entire volume, and preferably distributing these locations as uniformly as possible across the volume. An advantage is that additional constraints can be considered, such as risk areas to be avoided; for example, tissue that would be damaged when placed in or near a risk area by physically inserting and / or passing through the risk area and / or by an energy source such as an ablation tool or a brachytherapy seed.

[0019] The advantage of this invention is that the method can be used with readily available, inexpensive, disposable and / or simple template grids known in the art.

[0020] The advantage of this invention is that using a simple template grid can help avoid compatibility issues with more complex positioning aids, such as compatibility with magnetic resonance imaging, ultrasound imaging, and / or X-ray imaging.

[0021] The advantage of this invention is that it avoids complex robotic systems used for interventional tools with substantially free positioning, such as robotic systems for interventional tools with substantially continuous positioning in three (four, five, or six) translational degrees of freedom (rotation), while still providing many of the advantages of such complex systems in terms of accuracy. For example, while robotic systems, utilizing large degrees of positioning freedom, can allow for good optimization of treatment, they can be very costly, for example, in terms of initial investment, maintenance requirements, and training of clinical staff. The advantage of this invention is that it allows for the use of inexpensive, simple, and readily available treatment systems, such as grid templates and / or treatment planning systems, while still achieving high-quality treatment, for example, allowing for better optimization than traditional treatments relying on manually positioned grid templates.

[0022] The advantages of this invention are that a well-defined template grid can be achieved using an optimization procedure separable from the treatment planning based on the determined location, thereby reducing the overall complexity of the planning and keeping the global treatment plan tractable. The advantage lies in using a template grid to limit the possible locations of the interventional tools(s) to be considered in the planning, thus reducing complexity while providing a good set of available locations for use in the planning. Furthermore, due to the limited number of available locations, direct search or similar optimization strategies can be used in the planning, which may allow finding the global optimum of the treatment, for example, avoiding suboptimal (locally optimal) solutions.

[0023] The advantages of this invention lie in reducing reliance on clinician experience. For example, the automated localization method disclosed herein can improve clinician efficiency, avoid problems caused by limited experience in physician training, improve treatment outcomes, and / or increase repeatability, such as avoiding unnecessary variability caused by manual localization of the template grid. By reducing variability between different treatments due to template grid localization, the influence of other treatment variables may be more easily detected when analyzing clinical outcomes, thereby aiding in process optimization.

[0024] Furthermore, by ensuring good coverage of the target volume through available interventional pathways, the robustness of treatment relative to microgrid / patient movement can be improved. For example, when a better suitable pathway becomes available through good initial positioning via the template grid, the dose (radiation or ablation) can be distributed across more treatment delivery points, thereby reducing the risk of inaccurate delivery to only a few points.

[0025] The advantage of this invention is that it can effectively treat particularly small tumors without increasing the (spatial) tolerance margin due to inaccurate template grid positioning. For example, suboptimal grid positioning can significantly hinder the quality of the delivered treatment plan, especially for very small lesions. In the worst case, very small lesions may lie entirely between the grid aperture tracks, making them impossible to reach by the inserted catheter or needle. This situation necessitates increasing the margin around the target to reach the treatment volume, but at the cost of increased dose (or thermal ablation) to nearby healthy tissue.

[0026] The advantage of this invention is that it can provide a simple user interface and / or alignment procedure for locating the template grid.

[0027] In a first aspect, the present invention relates to a processing device for determining the position and / or orientation of a grid template relative to a human or animal body during a medical intervention. This grid template includes a plurality of holes defining corresponding grid hole tracks, and is adapted to support and guide at least one interventional tool along the grid hole tracks when inserted into the body through at least one of the holes during the intervention.

[0028] The processing device includes an anatomical spatial information processing unit for receiving and / or processing data representing at least one target space volume in the body.

[0029] The processing device includes a grid position sampler for generating multiple candidate positions and / or orientations of a grid template relative to at least one target space volume in the body.

[0030] The processing device includes a quality calculator for: calculating at least one quality metric representing the suitability of a candidate location of a raster template for an intervention process for each of a plurality of candidate locations and / or orientations.

[0031] The processing device includes a location selector for selecting a location and / or orientation from a plurality of candidate locations and / or orientations based on at least one quality metric.

[0032] The mass calculator is adapted to: determine, for each candidate location and / or orientation, the spatial relationship between each grid aperture trajectory of the grid template and the at least one target volume when positioned according to the candidate location and / or orientation. For example, the mass calculator can be adapted to: determine the intersection of each grid aperture trajectory of the grid template with the at least one target volume when positioned according to the candidate location and / or orientation.

[0033] The quality calculator is also adapted to: calculate at least one quality metric for each candidate location and / or orientation by at least considering values ​​indicating the geometric overlap and / or proximity of the grid aperture trajectory based on the determined spatial relationship with respect to at least one target volume, and / or values ​​indicating the therapeutic effect measurement of a medical intervention procedure when constrained by the determined spatial relationship.

[0034] In the device according to an embodiment of the invention, the value may include a value indicating a measure of the therapeutic effect of a medical intervention procedure when constrained by the determined spatial relationship, the measure of therapeutic effect representing the radiation dose or ablation effect received in the at least one target space volume when one or more radiation sources or ablation devices are positioned along the grid aperture trajectory.

[0035] For example, a measure of therapeutic effect may include the absolute or relative (e.g., percentage) volume of the target space that receives at least a predetermined radiation dose (e.g., at least a predetermined value in gray) when one or more radiation sources (e.g., emitting a predetermined radiation flux or having a predetermined intensity in becquerels) are positioned along a grid aperture trajectory. Similarly, a measure of therapeutic effect may include the total, average, or other aggregated statistics of the radiation dose received by the target space volume or a predetermined volume fraction thereof when one or more radiation sources (e.g., emitting a predetermined radiation flux or having a predetermined intensity in becquerels) are positioned along a grid aperture trajectory.

[0036] For example, a treatment effectiveness measurement may include the absolute or relative (e.g., percentage) volume of the target space receiving a predetermined amount of ablation energy when one or more ablation sources (e.g., based on predetermined source power and / or residence time) are positioned along a grid aperture trajectory. For example, a treatment effectiveness measurement may represent the absolute or relative volume of the ablated target space.

[0037] For example, treatment effectiveness measurements may include the absolute or relative volume of the target space that reaches a predetermined temperature (e.g., exceeding a predetermined temperature threshold) when ablated by one or more ablation probes and positioned along a grid aperture trajectory, for example, given a predetermined ablation power and / or residence time and / or other predetermined ablation parameters. Similarly, treatment effectiveness measurements may include the average, maximum, minimum, or other aggregated statistics of the temperature reached by the deposited ablation energy or the ablation source through heating.

[0038] In the device according to an embodiment of the invention, the value may include a first value indicating the degree of intersection between the candidate location and / or orientation (e.g., all) of the grid aperture trajectory and at least one target volume.

[0039] In the processing apparatus according to an embodiment of the present invention, the first value may include the total number of grid aperture trajectories intersecting at least one target volume, and / or the total length of the line segments corresponding to the intersection, and / or the average or other statistical measure of central tendency corresponding to the length of the line segments corresponding to the intersection, such as the median.

[0040] In the processing apparatus according to an embodiment of the present invention, the anatomical spatial information processing unit may be adapted to receive and / or process data representing at least one risk space volume in the body, such as a volume in the body that is used to avoid or reduce intersections with (multiple) grid hole trajectories and / or to avoid or reduce the proximity of the grid hole trajectories to the risk volume.

[0041] A quality calculator can be adapted to: for each candidate location and / or orientation, determine the intersection of each grid aperture trajectory of a grid template with the at least one risk volume when positioned according to the candidate location and / or orientation. The quality calculator can also be adapted to: for each candidate location and / or orientation, calculate at least one quality metric by considering at least a first value and a second value, the second value indicating the degree of intersection between the (e.g., all) grid aperture trajectories of the candidate location and / or orientation and the at least one risk volume.

[0042] In the processing apparatus according to an embodiment of the present invention, the second value may include: the total number of grid hole trajectories intersecting at least one risk volume, and / or the total length of line segments corresponding to the intersection with at least one risk volume, and / or the average value or other statistical measure of central tendency corresponding to the length of the line segments corresponding to the intersection with at least one risk volume.

[0043] In the processing apparatus according to an embodiment of the present invention, a quality calculator may be adapted to: for each candidate location and / or orientation, calculate at least one quality metric by considering at least the first value, optionally the second value, and the third value. The third value may indicate the minimum distance from the grid aperture trajectory to the center of the at least one target volume, or the minimum distance to at least one center of the at least one target volume.

[0044] In the processing apparatus according to embodiments of the present invention, at least one quality metric may be multiple quality metrics, and the quality calculator may be adapted to combine the multiple quality metrics into a synthetic quality metric based on a weighted sum. A location selector may be adapted to select a location and / or orientation from multiple candidate locations and / or orientations that reach the extreme values ​​of the synthetic quality metric.

[0045] In a processing apparatus according to an embodiment of the present invention, at least one quality metric may be multiple quality metrics, and the location selector may be adapted to select a first subset of the multiple candidate locations and / or orientations based on a first quality metric among the multiple quality metrics, and to select at least a second subset of the first subset based on a second quality metric among the multiple quality metrics that is different from the first quality metric. For example, optionally, the second subset may be further reduced by using one or more additional quality metrics via one or more nested subsets.

[0046] The processing apparatus according to embodiments of the present invention may include a user interface for receiving priority configuration from a user to select an ordered set or subset of the plurality of quality metrics, wherein a position selector may be adapted to select a first quality metric and a second quality metric based on the ordered set or subset.

[0047] In the processing apparatus according to an embodiment of the present invention, a grid position sampler can be adapted to generate a plurality of candidate positions and / or orientations by translating and / or rotating the position and / or orientation representation of a grid template over a plurality of different translation and / or rotation steps.

[0048] In a processing apparatus according to an embodiment of the present invention, a grid position sampler can be adapted for the translation and / or rotation over a plurality of different translation and / or rotation steps relative to an initial position and / or orientation.

[0049] The processing device according to embodiments of the present invention may include a user interface for receiving the initial position and / or orientation from a user.

[0050] In a processing apparatus according to an embodiment of the present invention, a grid position sampler can be adapted to determine the initial position and / or orientation by means of the following operations:

[0051] - Project at least one target space volume within the body onto a plane outside the body and / or tangent to the body surface, and determine the initial position as the center of the projection; or

[0052] - The initial position is determined by projecting the center of at least one target space volume in the body onto a plane outside the body and / or tangent to the body surface.

[0053] In a processing device according to an embodiment of the present invention, an anatomical spatial information processing unit may include an input port for receiving data in the form of at least one segmented medical image, wherein at least one target space volume and / or at least one risk space volume in the body is represented by a corresponding segmentation label.

[0054] In the processing apparatus according to an embodiment of the present invention, the anatomical spatial information processing unit may include an input port for receiving data in the form of at least one surface grid and / or parameter space descriptor of at least one target space volume and / or at least one risk space volume in the body.

[0055] In a processing device according to an embodiment of the present invention, an anatomical space information processing unit may include: an input port for receiving data representing at least one target space volume and / or at least one risk space volume in the body, the data being in the form of at least one medical image; and an image segmentation unit (3) for segmenting the at least one medical image to determine at least one target space volume and / or at least one risk space volume in the body.

[0056] The processing apparatus according to embodiments of the present invention may include a grid template alignment evaluator for receiving a position signal indicating the physical position and / or orientation of a physical grid template, and for providing a feedback signal indicating the position and / or orientation selected by a position selector, and / or indicating the physical position and / or orientation, and / or the relative position and / or orientation between the physical position and / or orientation and the selected position and / or orientation.

[0057] In the processing apparatus according to embodiments of the present invention, a grid template alignment evaluator can be adapted to simultaneously visualize physical location and / or orientation, as well as the selected location and / or orientation, using a user interface.

[0058] In the processing apparatus according to embodiments of the present invention, the user interface can be adapted to display the physical location and / or orientation, as well as the selected location and / or orientation, in different display styles.

[0059] In the processing apparatus according to an embodiment of the present invention, the user interface can be adapted to display the physical location and / or orientation and the basic alignment of the selected location and / or orientation in a different display style (different from the aforementioned style).

[0060] In the processing apparatus according to embodiments of the present invention, the feedback signal may include an audio signal to indicate a measurement of the difference between the selected location and / or orientation and the physical location and / or orientation.

[0061] In a processing apparatus according to an embodiment of the present invention, the feedback signal may include an actuator signal for controlling one or more actuators adapted for positioning the physical grid template.

[0062] In a second aspect, the present invention relates to a clinical workstation comprising an apparatus according to an embodiment of the first aspect of the present invention.

[0063] In a third aspect, the present invention relates to a computer-implemented method for determining the position and / or orientation of a grid template relative to a human or animal body during a medical intervention, wherein the grid template includes a plurality of holes defining corresponding plurality of grid hole trajectories, and wherein the grid template is adapted to support and guide at least one interventional tool along such grid hole trajectories when inserted into the body through at least one of the holes during the intervention. The method includes receiving and / or processing data representing at least one target space volume in the body, generating a plurality of candidate positions and / or orientations of the grid template relative to the at least one target space volume in the body, and for each candidate position and / or orientation, determining, for each grid hole trajectory of the grid template, a spatial relationship with the at least one target volume when positioned according to the candidate position and / or orientation, such as the intersection of each grid hole trajectory with the at least one target volume. The method further includes, for each of the plurality of candidate positions and / or orientations, calculating at least one quality metric representing the fit of the candidate position of the grid template for the intervention procedure.

[0064] The calculation of at least one quality metric may be considered as indicating a value of geometric overlap and / or proximity of the grid aperture trajectory relative to at least one target volume based on the determined spatial relationships. The calculation of at least one quality metric may also be considered as indicating a value of the therapeutic effect of a medical intervention procedure when constrained by the determined spatial relationships.

[0065] For example, at least one quality metric can be calculated by considering at least a first value indicating the degree of intersection between the grid aperture trajectory, which indicates the candidate location and / or orientation, and at least one target volume, and a location and / or orientation can be selected from a plurality of candidate locations and / or orientations based on the at least one quality metric.

[0066] In a fourth aspect, the present invention relates to a computer program product comprising executable computer program code for implementing a computer-implemented method according to an embodiment of the present invention when the computer program product (executable computer program code) is executed on a processor (e.g., on a computer device).

[0067] The independent and dependent claims describe the specific and preferred features of the invention. Features of the dependent claims may be combined with features of the independent and other dependent claims in a manner deemed appropriate, and not necessarily only as expressly stated in the claims. Attached Figure Description

[0068] Figure 1 An apparatus and system according to an embodiment of the present invention are shown.

[0069] Figure 2 The diagram shows the intersection of a grid aperture trajectory (e.g., a treatment delivery path) with a target volume of interest (e.g., a cancerous lesion) used to illustrate an embodiment of the invention.

[0070] Figure 3 The diagram illustrates two distinct candidate locations for a grid template used to illustrate an embodiment of the invention, as well as the minimum distance between the grid aperture trajectory and the geometric center of the volume of interest.

[0071] Figure 4 A visualization is shown to illustrate the physical grid position and the selected grid position (i.e., the target position) for an embodiment of the present invention.

[0072] Figure 5 A grid template is shown, which is used to illustrate an embodiment of the present invention and is mounted on a stepper device.

[0073] Figure 6 A stand for supporting a grid template and a stepper device, illustrating an embodiment of the present invention, is shown.

[0074] Figure 7 The controllable position and orientation of a grid template for illustrating an embodiment of the present invention using a stepper device (e.g., manually controllable).

[0075] Figure 8 A method according to an embodiment of the present invention is shown.

[0076] These accompanying drawings are illustrative and not limiting. Elements in the drawings are not necessarily shown to scale. The invention is not necessarily limited to the specific embodiments shown in the drawings. Detailed Implementation

[0077] Although exemplary embodiments are described below, the invention is limited only by the appended claims. The appended claims are expressly incorporated herein by reference, wherein each claim and each combination of claims permitted by the dependent structure defined by the claims forms a separate embodiment of the invention.

[0078] As used in the claims, the word "comprising" is not limited to the features, elements, or steps described herein, and does not exclude additional features, elements, or steps. Therefore, this specifies the presence of the mentioned features without excluding the presence or addition of one or more other features.

[0079] Various specific details are presented in this specific embodiment. Embodiments of the invention can be performed without these specific details. Furthermore, for the sake of clarity and brevity, well-known features, elements, and / or steps are not necessarily described in detail.

[0080] In a first aspect, the present invention relates to a processing device for determining the location of a grid template during a medical intervention, wherein the grid template is used to support and guide at least one interventional tool, such as a needle, ablation tool, brachytherapy source, or catheter, into the anatomical volume of interest through at least one selected hole in the grid template.

[0081] Figure 1 An illustrative device 1 according to an embodiment of the present invention is shown. This device may include a computer, for example, specifically programmed to implement the described device. Such a computer may include inputs and outputs, such as multiple communication interfaces for receiving and transmitting data, for example, via data carriers and / or communication network interfaces. Such inputs and outputs may also include user interface hardware, such as human interaction devices (e.g., keyboards, mice, voice translators, touch interfaces, gyroscopes, or accelerometers, etc.) for receiving input from human users, monitors for presenting information to users, speakers, printers for presenting information onto physical carriers (e.g., paper), 3D printers for generating three-dimensional physical models of data, and other such elements known in the art.

[0082] A computer may include a general-purpose processor for executing instructions (e.g., computer code) and memory for storing such instructions. A computer may include memory for storing data, such as for operating according to instructions. The device is not necessarily limited to a general-purpose computer, but may also include application-specific integrated circuits (ASICs) and / or configurable processing hardware, such as field-programmable gate arrays (FPGAs). Furthermore, the device may be included in a single processing device, such as a computer, but may also be distributed across multiple such devices operatively connected to each other, for example, enabling the processing described herein to be performed through the combined action of server and client devices or parallel processing systems such as computing clusters.

[0083] Processing device 1 is adapted to determine the location of a grid template during a medical intervention. This medical intervention can be lesion treatment, a biopsy, or another medical intervention performed by specifically inserting an interventional tool into a spatial volume. For example, a medical intervention may include a biopsy or pathological mapping of an anatomical region, such as a lesion or part of an organ or tissue suspected of being caused by a disease or disorder. For example, lesion treatment can refer to percutaneous lesion treatment, such as percutaneous cancer treatment, such as brachytherapy for cancer, ablation procedures, such as cryoablation, thermal ablation, microwave ablation, (focused) ultrasound ablation, radiofrequency ablation, laser ablation, etc., or treatments in which a lesion energy source is used to activate sensitized tissues and / or cells, such as photodynamic therapy. For example, to treat a tumor, a physician may choose a form of brachytherapy or ablation, for example, based on available means, lesion size and location, affected organs, etc. However, in such procedures, it is common to manually place the grid template on (or at least close to) the skin surface and insert an interventional tool (e.g., a biopsy needle, ablation device, needle or catheter preloaded or loadable with brachytherapy seeds, etc.) into the body through one or more guide holes in the grid template, typically selected from a large number of possible (selectable) holes. Another example of this procedure could be the implantation of a microdevice (e.g., a microstimulator) or other structure (e.g., a timed-release capsule for releasing a drug compound) into a specific site within the body.

[0084] A grid template can also be referred to as a guiding grid frame or a treatment grid. As is known in the art, a grid template can be a rigid or flexible grid template. The grid template can be radiopaque, for example, to avoid interference with ionizing radiation used in patient imaging when positioning the grid template for the procedure. In this disclosure, terms such as 'grid,' 'template,' 'template grid,' and 'grid template' are considered equivalent and interchangeable, referring to the same guiding grid frame used in the interventional procedure. The grid template includes a plurality of holes, i.e., through-holes, located at different locations on the grid template. For example, the grid template can have a main surface on which the holes are distributed, such that each hole protrudes through the grid template from the main surface to a surface opposite the main surface. For example, one dimensional component of the grid template can be substantially smaller than the other two (Cartesian) dimensional components, such that two "main" surfaces, typically on opposite sides of the template, can extend into two larger dimensions. One such main surface can be adapted to contact (or face) the patient's skin during use, while the opposing main surface allows access to the holes, enabling tools, such as needles, pins, catheters, and other such elongated elements, to be inserted from that side into the contact side and further inserted into the patient's body at a specific location (the location of the holes) and orientation (e.g., by guiding the tool through the holes) along that path. Not limited to this, the grid template can include such holes arranged in rows and columns (hence the term "grid," e.g., a rectangular grid). This does not preclude other distribution patterns of the holes, such as polar grids or hexagonal grids. The distribution pattern can be regular or irregular, uniform or non-uniform. This template can be disposable or reusable. The template can be rigid, flexible, or have some degree of limited flexibility. The grid holes can be spaced apart from each other (i.e., relative to adjacent holes) at distances ranging from, for example, 1 mm to 20 mm. A typical example is a template with an inter-hole distance ranging from 2 mm to 10 mm, e.g., 3 mm to 8 mm, or, for example, 5 mm. These holes can have diameters suitable for a predetermined needle diameter, for example, a needle diameter in the range of 14 to 18 (but not limited to), such as 14g, 17g, or 18g. The number of holes can (but is not limited to) range from, for example, 9 to 1000, typically in the range of 25 to 225, such as 25, 36, 49, 64, 81, 100, 121, 144, 169, or 225 holes. While these examples are based on a regular grid with the same number of rows and columns, it should be understood that in the embodiments, the grid is neither required to be a regular rectangular grid nor is the number of rows required to equal the number of columns.

[0085] The grid template includes multiple holes (through holes) that define corresponding grid hole tracks for needles, catheters, or other elongated interventional tools (when inserted through the holes). The grid template can have a considerable width, such that the direction of the grid hole tracks is constrained to a specific orientation, such as perpendicular to the surface of the grid template (which may or may not consider local surface curvature, such as in the case of a flexible grid template). However, embodiments are not necessarily limited to this. For example, other means can be used to control the insertion direction, or the holes can be positioned at angles other than right angles relative to the surface.

[0086] Technicians will understand that the positioning of the grid template can be important for the success of the procedure. Typically, unless otherwise instructed by a medical professional, only the grid aperture trajectory that intersects (e.g., enters) the target volume (e.g., the lesion to be treated) can be used for interventional procedures, such as for treatment delivery. For example, in brachytherapy reverse planning methods, such as... Figure 2 The target lesion intersection segments shown can be used to sample and determine a set of dwell positions for which the radiation source can remain for a given optimal time. Therefore, both automated backward planning and manual forward planning solutions can benefit from optimal grid placement. For example, the needle trajectory through the grid apertures is preferably designed to intersect the segmented anatomical structures as much as possible. The success and effectiveness of treatment, as well as the prevention of post-treatment complications, may be particularly sensitive to the initial grid placement of very small lesions to be treated.

[0087] In its use, device 1 determines the location of the grid template to be used in this procedure, such as the optimal (or at least good) placement of the grid template to allow access to the spatial volume by inserting (multiple) interventional tools through one or more holes in the grid template. This location may, for example, depend on the size and location of the volume, such as the location and size of a tumor, and the parameters of the grid template, such as the specifications provided by the grid template manufacturer. By automatically optimizing the grid template location, reliance on physician experience can be advantageously reduced, and physician efficiency can be improved by reducing or eliminating the time spent manually determining the appropriate location. For example, in conventional methods, a physician may need to position the grid template, select a set of tool locations, and determine the corresponding set of tool parameters. Once the grid template is positioned, a known solution in the prior art is to automatically (or computationally assisted) select tool locations on the grid hole trajectory provided by the grid template and determine the appropriate parameters. For example, manual forward planning or automated backward planning solutions can be applied to find the optimal set of delivery parameters (e.g., brachytherapy catheter location, thermal ablation probe location, dwell time, ablation time / power value, etc.).

[0088] The processing device 1 is adapted (e.g., programmed or configured) to receive spatial data representing at least one target space volume within a patient’s body, wherein, according to a medical intervention procedure, at least one interventional tool will be inserted into the at least one target space volume through at least one hole in a grid template.

[0089] The processing device may also be adapted (e.g., programmed for, configured for) to receive spatial data representing at least one risk space volume within a patient's body, at least the interventional tool should avoid (e.g., by moving away from a distance margin) the at least one risk space volume and / or should not penetrate the at least one risk space volume along its insertion path. For convenience, at least one target space volume and, optionally, at least one risk space volume may be collectively referred to below as "(a plurality of) volumes of interest".

[0090] Therefore, the processing device 1 includes an anatomical spatial information processing unit 2 for receiving and / or processing data representing at least one target space volume within the patient's body; and optionally, at least one risk space volume within the body. The spatial information processing unit may be or include an input port for receiving said data, such as via a digital communication network, a physical data carrier, or a dedicated interface with a medical imaging device, such as a bus interface. The data may be received in the form of a medical image, such as a three-dimensional volumetric image of at least a portion of the body including the target space volume and / or the risk space volume. Such a medical image may include (e.g., three-dimensional or tomographic) images obtained by X-ray computed tomography (CT), magnetic resonance imaging, nuclear medicine imaging, ultrasound imaging, or other medical imaging methods (e.g., elastography, optical CT, photoacoustic imaging, magnetic particle imaging, but not limited to these examples). The medical image may be processed to define (multiple) volumes of interest, for example, in the form of image overlay annotation voxels assigned to (multiple) volumes of interest, or the medical image may consist of the definition of (multiple) volumes of interest, i.e., it may be a segmented image. Alternatively, data can be received in the form of descriptors for (multiple) volumes of interest, such as defining (multiple) surface meshes of (multiple) volumes of interest, for example, defining the volume of interest, or each volume of interest, as a set of vertices, edges, and faces of a polyhedral object in a reference coordinate space. Such faces can include triangles, quadrilaterals, and / or other polygons (n-gons; e.g., convex polygons, even concave polygons). Descriptors can also be defined in another suitable format, such as a parameter definition of (each) of (multiple) volumes of interest, for example as parameters of one or more spheres, cubes, non-uniform rational basis splines (NURBS), or other parametric shapes, or, for example, a volume mesh, for example, also including explicit volume information. While descriptors for (multiple) volumes of interest can generally directly define the volume (or its closed surface), random or fuzzy definitions of the volume are not necessarily excluded (e.g., probabilistic graphs).

[0091] The anatomical spatial information processing unit 2 may also include a (volume) image segmentation unit 3 for segmenting the medical image to delineate (multiple) volumes of interest in the medical image, for example, where the data does not yet include segmentation information or another form of definition of (multiple) volumes as described above. Suitable segmentation algorithms are known in the art and may include manual segmentation (e.g., using a suitable user interface 7), semi-automatic segmentation, and / or automatic segmentation. Not limited thereto, some examples of such segmentation methods known in the art include voxel value thresholding, clustering methods, histogram-based methods, edge detection, region growing methods, partial differential equation-based methods, variational methods, graph partitioning methods, watershed transform-based methods, multi-scale methods, machine learning-based methods (e.g., trainable methods), and / or any combination thereof.

[0092] Therefore, the processing device can receive definitions of (multiple) volumes of interest, or such definitions can be determined otherwise by processing the received data (e.g., image data), which may implicitly contain such information. Thus, all regions of interest (e.g., target lesions and organs at risk) can be segmented in a preprocessing step, for example, provided to the device by processing performed by the device (e.g., based on the received image data) or by a combination of both (e.g., by providing and refining the initial segmentation through an automated, interactive, or manual procedure performed by the device).

[0093] The processing device includes a grid position sampler 4 for generating multiple candidate positions of a grid template relative to (multiple) volumes of interest, e.g., in a (implicit or explicit) shared reference coordinate system. Generating multiple candidate positions may include translating and / or rotating the grid template over multiple different translation and / or rotation steps. For example, the grid position sampler may sample the position (and optionally, orientation) of the grid template over a set of translation steps and / or rotation angles. An initial position may be automatically determined and / or specified by the user, e.g., using the device's user interface 7. For example, the user may provide a best guess at the initial grid position (x0, y0) based on patient anatomy and / or prior knowledge and / or experience to initialize the localization method performed by the device. The user-defined initial position may be validated by the device, e.g., to check whether it allows complete containment of all target volumes, e.g., defined cancerous lesions. When the term 'sampling' is used, the sampling may be a deterministic determination of candidate positions, e.g., by direct enumeration, or it may be random sampling, e.g., by randomly sampling from a distribution function of candidate positions. A reference to 'location' can refer to (multiple) positional coordinates, (multiple) angular orientation coordinates, and / or combinations thereof. Therefore, 'location' should not be interpreted narrowly as just a point in space, but can also refer to one or more angles or orientations, or a combination of points and orientations in space, such as a localized vector (e.g., "localized" relative to a free or unbound vector).

[0094] The initial position can be determined automatically, either by using a fixed, predetermined location or by a simple trial-and-error method, such as projecting the target volume of interest onto the skin surface of the body, for example, along a fixed coordinate axis or along the surface normal of the skin surface. For example, the initial grid position can be determined automatically by projecting the geometric centroid of the target volume (e.g., a single cancer lesion) onto a grid x,y plane (which may be defined, for example, by a plane parallel to the skin surface or its approximation). Similarly, in the case of multiple target volumes, such as multiple lesions, the spatially averaged position of such projected centroids calculated for each target volume can be used. Alternatives can be readily envisioned, such as using other centrality measures or using the centroids of a convex hull of multiple target volumes. This automatic determination of the initial position can also be performed when a user-provided initial position is deemed unsuitable, for example, if it allows insufficient access to the (multiple) target volumes; see, as described above, verification.

[0095] Translation steps can be determined directly and deterministically, for example, by using integer (e.g., signed) multiples of a predetermined step size in one, two, or three coordinates. This step size (or the step size used for different translation and / or rotation components) can be predetermined or can be configured by the user using the user interface 7.

[0096] For example, for all combinations of i = {-K,-K+1…,0,…, K-1,K} and j = {-L,-L+1,-L+2,…,0,…,L-2,L-1,L}, a horizontal step size s can be used (either pre-defined or specified by the user using user interface 7). x and vertical step size s y (They can be equal) Define the candidate positions relative to the initial positions x0, y0 as [x, y] = [x0 + is x ,y0+js y ], used to cover 2K.s x ×2L.s y The predetermined region range. It does not necessarily exclude (nor necessarily include) consideration of additional steps in the z-direction perpendicular to the x,y plane (or more precisely, include steps whose z-component is not constant in all considered steps). Similarly, rotations can be considered, for example, using angular steps s. θ Rotation can be performed in the x,y plane. Rotation can also be considered outside the x,y plane, for example, using two or even three complementary angular components. Therefore, a discrete (finite) set of positions (and / or orientations) of a raster template spanning 1, 2, 3, 4, 5, or even 6 (rotational) translational components can be generated. For good position estimates, at least two components are likely preferred, such as two complementary translational components (even optimization in a single direction is useful for some embodiments), such as the x and y components. A third component, such as rotation in the x,y plane, can also be considered to find positions that might allow for further optimization. Similarly, including additional degrees of freedom may allow for better optimized position estimates. However, embodiments can be designed with a trade-off between optimization quality and complexity in mind. For example, the complexity associated with the number of sampling positions can be exponentially O(n^2). k ) to scale, where k is the number of degrees of freedom considered in the transformation step.

[0097] Although the process of generating multiple candidate locations is described as a separate step, those skilled in the art will understand that the iteration over multiple candidate locations can also be performed linearly, for example, the location / orientation does not need to be pre-calculated and stored for further processing steps, but can be determined "on-the-fly" in that additional processing step.

[0098] While examples of uniform grid sampling of coordinates (potentially including rotational components) are given, it is understood that embodiments are not necessarily limited to uniform sampling. For example, polar sampling may be used to account for more locations closer to the initial position than those farther away. Alternatively, random sampling of the location space, or variable step sizes, may be used, for example, to increase the sampling density near the initial position. This location (or orientation) sampling process may include sampling at horizontal (“x”) and vertical (“y”) positions, which may, for example, be defined as a plane perpendicular to the grid template at its initial position, and may be selected or determined to be tangential to the patient’s skin surface at (or near) the initial position (and not necessarily limited to tangential orientation).

[0099] Displacement is not necessarily limited to linear displacement (and / or its corresponding rotation); the curvature of the body surface can also be considered. For example, sampling locations (e.g., uniform Cartesian sampling locations) can be mapped onto the body surface to constrain the sampling locations to where the grid template is placed in contact with the skin. For example, when using a flexible grid template, locations can be sampled across a predetermined area of ​​the skin, possibly including rotational components in the (curved) plane. However, even for a rigid template, the orientation of the grid template can follow the contours of the body, allowing locations to still be sampled on the skin surface. It should be noted that, due to its rigidity and the curvature of the skin, a rigid template may not contact the skin at all points on the grid template (nor intersect with the skin surface). Grid location samplers can be adapted to account for this, for example by sampling locations (and / or relative orientations) on the skin surface (which can be determined in the segmentation step based on imaging data) and adjusting each location by the minimum distance required to avoid collisions (i.e., the model of the rigid template intersecting with the body), for example, in a direction perpendicular to the skin surface. Alternatively or additionally, adjustments to the orientation can also be determined at that location(s) to avoid collisions. For flexible grid templates, it can be assumed that the grid template is flexible enough to conform to the skin surface, or a certain degree of flexibility can be considered to reject locations where the skin curvature is too strong, or collision avoidance normal displacement (and / or orientation adjustment) can be determined when the grid template is bent to the maximum extent to conform to the local curvature within its physical tolerance margin for bending.

[0100] Device 1 includes a quality calculator 5 for calculating at least one quality metric representing the fitness of a candidate location for a grid template of an intervention process, for each of a plurality of candidate locations. The mention of a “quality” calculator is for disclosure purposes only, to avoid confusion with other features, and is not intended to imply anything other than the function performed by this component. Even when a quality metric is mentioned, for example, a quality metric can typically increase in value if the location’s fitness is high, but the cost function is considered completely equivalent and is therefore also referred to as a “quality metric,” for example, a cost function can typically decrease if the fitness increases. The quality metric may also be referred to as an objective or objective function.

[0101] The quality calculator 5 is adapted to: determine the spatial relationship between each grid hole trajectory of the grid template and at least one (e.g., with each) target volume when it is positioned according to the candidate position and / or orientation, for each candidate location and / or orientation.

[0102] For example, the mass calculator 5 can be adapted to determine the intersection of each grid aperture trajectory with the target volume or each target volume, for example, as... Figure 2 As shown. The quality calculator can also determine the spatial relationship between each grid aperture trajectory and the risk volume or each risk volume, such as the intersection of each grid aperture trajectory with the risk volume or each risk volume.

[0103] For example, a quality calculator may include a model of a grid template, parameterized as a function of the grid template's position (e.g., each candidate position) and / or orientation as parameters for evaluation, in a coordinate space specifying (or applying minute coordinate transformations to allow determination of the intersections) the volumes of interest(s). While the term "model" is used, it should be understood that such a model may be particularly simple, such as a set of localized vectors defining the trajectory of each grid aperture relative to a local coordinate system, where transformations of this local coordinate system according to the position / or orientation in the evaluation allow determination of the grid aperture trajectory at each position / or orientation, and thus also allow determination of the intersections. It should also be understood that such a model can be more complex, for example, taking into account the deformation properties of the grid template. It should be understood that a quality calculator may include multiple models of different grid templates, or models of grid templates specified in a form dependent on grid template parameters, such as grid aperture spacing, grid configuration, grid size, etc. User interface 7 can be used to select a model corresponding to the grid template intended for use in the process, and / or configure such grid template parameters (even if embodiments implementing only a single fixed grid template model are not necessarily excluded).

[0104] Each grid aperture trajectory corresponds to a line segment of a line passing through an aperture in a predetermined direction relative to the orientation of the grid template, for example, the direction in which the aperture penetrates the template, such as perpendicular to the main surface of the grid template. Thus, the predetermined direction can correspond to the direction in which an interventional tool, such as a needle or catheter (or including needles or catheters; not limited to other generally elongated interventional tools of other types for insertion into the body), is guided by the grid template as it is inserted through the aperture. Therefore, an intersection can correspond to a line segment of a line that coincides with the volume of interest. The calculated intersection can include an explicit identifier of such a line segment, but additionally or alternatively, it can also include values ​​derived from it, such as the length of the line segment, or simply a Boolean indicator indicating whether the grid aperture trajectory intersects with the volume of interest, such as indicating whether an intersection exists, or indicating whether the length of the line segment is not zero.

[0105] Calculating at least one quality metric includes: for each candidate location and / or orientation, calculating at least one quality metric by considering at least the values ​​indicating: the geometric overlap and / or proximity of the grid aperture trajectory relative to at least one target volume based on the determined spatial relationships; and / or the measurement of the therapeutic effect of the medical intervention procedure when constrained by the determined spatial relationships.

[0106] Calculating at least one quality metric may include calculating a value indicating the therapeutic effect of a medical intervention procedure when constrained by the determined spatial relationships. Thus, a therapeutic effect measurement may represent the radiation dose or ablation effect received in at least one (or each) target space volume when one or more radiation sources or ablation devices are positioned along the grid aperture trajectory.

[0107] For example, a measure of therapeutic effect may include the absolute or relative (e.g., percentage) volume of the target space that receives at least a predetermined radiation dose (e.g., at least a predetermined value in gray) when one or more radiation sources (e.g., emitting a predetermined radiation flux or having a predetermined intensity in becquerels) are positioned along a grid aperture trajectory. Similarly, a measure of therapeutic effect may include the total, average, maximum, minimum, median, predetermined percentage (e.g., first and / or third quartiles), or other aggregated statistics of the radiation dose received by the target space volume or a predetermined volume fraction thereof when one or more radiation sources (e.g., emitting a predetermined radiation flux or having a predetermined intensity in becquerels) are positioned along a grid aperture trajectory.

[0108] For example, a treatment effectiveness measurement may include the absolute or relative (e.g., percentage) volume of the target space that receives a predetermined amount of ablation energy when one or more ablation sources (e.g., based on predetermined source power and / or residence time) are positioned along a grid aperture trajectory. For example, a treatment effectiveness measurement may represent the absolute or relative volume of the ablated target space.

[0109] For example, therapeutic efficacy measurements may include the absolute or relative volume of the target space that reaches a predetermined temperature (e.g., exceeding a predetermined temperature threshold) when positioned by one or more ablation probes along a grid aperture trajectory, for example, given a predetermined ablation power and / or residence time and / or other predetermined ablation parameters. Similarly, therapeutic efficacy measurements may include the average, maximum, minimum, or other aggregated statistics of the deposited ablation energy or the temperature reached by the ablation source through heating.

[0110] For example, for each candidate location / orientation, the optimal location of the radiation source or ablation device can be determined along each trajectory to determine a measure of therapeutic effect, or multiple such locations along each trajectory can be considered; for example, two or more sources, such as a predetermined number of sources, can be distributed along the trajectory. The device may include a treatment planner for determining a suitable treatment plan constrained by the candidate locations / orientations of the grid to determine a measure of therapeutic effect. As is known in the art, forward or backward planning algorithms can be applied to each candidate location / orientation to determine a measure of therapeutic effect. However, simplified, e.g., approximate, treatment planning algorithms can be used to determine approximate values ​​of the measure of therapeutic effect, allowing efficient estimation of the therapeutic effect when using a specific location / orientation with a grid template, and after selecting the optimal location / orientation based on this approximate metric, a more detailed, e.g., more accurate, treatment planning algorithm can be applied to propose a treatment plan to be implemented. Furthermore, in embodiments, for efficiency reasons, simplified methods can be applied that do not require detailed treatment planning to measure the suitability of the candidate location / orientation, e.g., a metric based on the intersection of the trajectory with the target volume(s). Advantageously, this method allows for the determination of an appropriate configuration of the grid template without requiring detailed knowledge of the applied procedure; for example, it can be applied solely based on geometric considerations without regard to the specific process to be performed. However, as previously stated, more sophisticated methods that advantageously utilize knowledge of the process to be applied are not necessarily excluded in embodiments according to the invention.

[0111] For example, calculating at least one quality metric may include calculating at least one target value indicating the degree of intersection of all grid aperture trajectories with the target volume(s) when the grid template is positioned (and / or oriented) according to a candidate location. The target value may include the total number of grid aperture trajectories intersecting with the target volume(s). The target value may include the total length of the line segments intersecting with the target volume, such as the sum of the lengths of all such intersecting line segments. The target value may include the average length of the line segments intersecting with the target volume, such as the sum of the lengths divided by the number of grid aperture trajectories intersecting with the target volume. The at least one quality metric may be calculated as a higher value corresponding to the target value, indicating a higher suitability of the candidate location of the grid template for the intervention procedure. Therefore, based on the quality metric, the location / orientation of the grid template can be preferentially selected to maximize the total number of available grid apertures reaching the target volume, and / or to maximize the total path length through which the intervention tool can be positioned within the target volume via the grid aperture trajectories.

[0112] Calculating at least one quality metric may include calculating at least one risk value indicating the degree of intersection of all grid aperture trajectories with the (or all)(multiple) risk volumes when the grid template is positioned (and / or oriented) according to a candidate location. The risk value may include the total number of grid aperture trajectories intersecting with the risk volumes. The risk value may include the total length of the line segments intersecting with the risk volumes, such as the sum of the lengths of all these intersecting line segments. The risk value may include the average length of the line segments intersecting with the risk volumes, such as the sum of the lengths divided by the number of grid aperture trajectories intersecting with the risk volumes. At least one quality metric may be calculated such that a higher value for the risk value indicates a lower suitability of the candidate location of the grid template for the intervention procedure. Therefore, based on the quality metric, the location / or orientation of the grid template may be preferentially selected, minimizing the total number of available grid apertures reaching the risk volume, and / or minimizing the total path length by which the intervention tool can be positioned within the risk volume via the grid aperture trajectories.

[0113] Calculating at least one quality metric may include calculating at least one centrality value, which indicates the minimum distance from the grid aperture trajectory to the center of the target volume(s). This distance may be a Euclidean distance, but does not necessarily exclude other suitable distance metrics, such as Manhattan (or “taxicab”) distance, r Chebychev (or “chessboard” or “infinite norm”) distance, or typically a Minkowski distance of any integer or non-integer (but greater than 1) order p.

[0114] This minimum value can be calculated as the minimum of all such distances calculated for all grid aperture trajectories of the candidate locations / orientations under consideration. These distances can be the distance between the grid aperture trajectory (or equivalently, the determined intersection with the target volume) and the center of the target volume, where the center can be the geometric center, centroid, centroid, center point, center of mass, Chebyshev center, center of the convex hull of the target volume, center of the smallest closed sphere around the target volume, or another geometric measure of the centrality of the spatial volume. When multiple target volumes are defined, the center can refer to the geometric center (or other centrality measure) of the collective (union) target volumes, or the minimum distance can be calculated separately for each target volume. For example, the centrality value can indicate the mean, median, average, or similar measure of the minimum distances obtained for the target volumes. Alternatively, the centrality value can indicate the maximum of the minimum distances between the grid aperture trajectories and the target volumes' centrality measures across all target volumes. Thus, the location / orientation of the grid template can be preferentially selected based on a mass metric that minimizes the nearest distance to the center of that (or each) target volume that can be approached via the grid aperture trajectories. Therefore, it is encouraged to select grid location / orientation to maximize the probability that the grid aperture trajectory passes through the center of (multiple) target areas. This improves the symmetry of the optimized interventional procedure planning relative to the shape of (multiple) lesions at hand and enhances robustness to minor patient / bed movements during the interventional procedure. For example, Figure 3 Two different candidate positions for the grid template are shown. It can be seen that the candidate positions for grid template 23, as shown on the left, achieve a smaller average nearest grid distance than the candidate positions shown on the right. Figure 3 The image shows the centroid 21 of the two target volumes 22 (projected onto the plane of the grid template).

[0115] For clarity, references to “target value,” “risk value,” and “centrality value” should be considered merely as naming conventions to avoid confusion, and not as implying any special properties other than those mentioned above. Similarly, these values ​​can be referred to as “first value,” “second value,” and “third value,” rather than implying any particular ordinal property through such numerical naming.

[0116] Calculating at least one quality metric may include calculating multiple such quality metrics, such as one or more of the mentioned target values ​​(e.g., based on the number of intersecting segments, the total length of the intersecting segments, and / or the average of the intersecting segments), one or more mentioned hazard values ​​(e.g., based on the number of intersecting segments, the total length of the intersecting segments, and / or the average of the intersecting segments), and / or one or more mentioned centrality values ​​(different metrics of centrality and / or methods may be considered to account for multiple target volumes). These quality metrics may be combined into a synthetic quality metric, for example, by calculating a weighted sum of the different quality metrics. The weights of such a weighted sum may be predetermined or configurable, for example, by receiving input from the user through a user interface 7. Each quality metric may be appropriately scaled, for example, normalized, so that the weights have comparable effects to comparable values ​​of the weights. For example, each value of the terms forming the synthetic quality metric may be divided by its known or assumed maximum value, such that the weights may be selected in the range of 0 to 1, representing “irrelevant” or “not considered” to “maximum relevance,” respectively. It should also be noted that some of the aforementioned quality metrics should be considered as penalties, while others should be considered as targets, and therefore should be combined with appropriate flags, other scaling inversions, to take them into account. For example, the number of intersections with risk volumes can be subtracted from the number of intersections with target volumes, or its effect can be reversed in other ways before being combined into the synthetic quality metrics (applied to possible normalization of these terms as described above). Alternatively or additionally, multiple quality metrics can be evaluated separately, for example, first selecting suitable locations / orientations based on the extreme values ​​achieved for a first quality metric, and then using a second (third, ...) quality metric to further reduce the number of selected locations / orientations to ultimately achieve only one (or a few) suitable locations / orientations. Specifically, some of the illustrative quality metrics discussed above can present integer values, such as multiple intersections, so that multiple candidate locations / orientations can present the same value of such discrete quality metrics, such as the maximum (or minimum) value of that value. Similarly, for non-discrete (continuous) quality metrics, a (predetermined or configurable) tolerance margin threshold can be considered to select multiple locations / orientations that are considered sufficiently close to the extreme values, to be taken into account in another step using another quality metric to further reduce the number of selected locations / orientations.

[0117] Device 1 includes a location selector 6 for selecting a location and / or orientation from a plurality of candidate locations / or orientations based on at least one quality metric, such as for selecting a location / or orientation that reaches an extreme value (maximum or minimum value) for one of at least one quality metric and / or for a composite quality metric.

[0118] For example, in embodiments where multiple quality metrics are evaluated separately (i.e., where these quality metrics are not jointly evaluated as a composite quality metric), the user interface 7 can be adapted to receive priority configurations from the user to select the quality metrics to be evaluated and their evaluation order. Thus, the user can select at least a first quality metric for a first selection of candidate locations / orientations, and the user can select at least a second quality metric from the candidate locations / orientations selected in the first selection for a second selection. The user can select a third or even further quality metric to further reduce the number of selected locations / orientations. Therefore, the selector 6 can select locations / orientations by implementing a dictionary-ordered approach, where the user provides a set of targets (quality metrics) ordered by priority. However, in other embodiments, such a priority order can be fixed and predetermined, or it can be achieved using only a single (e.g., composite) quality metric.

[0119] In the first illustrative example, the selector can implement a dictionary-order approach. Here, the user determines the set of objectives ordered by priority, for example, a highest priority for achieving the maximum number of grid aperture tracks intersecting with (multiple) target volumes, and a lower priority for achieving the maximum average intersection length of the grid aperture tracks with (multiple) target volumes. In this approach, the selector can first select candidate positions / orientations that achieve the maximum number of grid aperture tracks intersecting with (multiple) target volumes. If this maximum value is achieved through a single grid aperture track, the solution can be provided as output, without even needing to process the second priority metric / objective. Otherwise, as a second step, within a subset of grid positions / orientations that equivalently achieve the maximum number of intersections, the best candidate positions / orientations that also produce the maximum average intersection length can be selected. As mentioned above, the selection or priority of other metrics may differ, possibly including a third, fourth, ... metric with lower priority. After evaluating all quality metrics in their assigned order, if more than a single candidate position / orientation remains selected, one can be randomly chosen for output, or all selected configurations can be output to allow the user to manually decide which configuration to use.

[0120] In the second illustrative example, the synthetic quality metric can be constructed by a weighted sum of all quality metrics (e.g., the quality metrics discussed above). The user can choose which quality metrics to use and assign corresponding importance weights. Importance weights can be relative values ​​in the interval [0, 1], where 0 represents "no relevance" and 1 represents "maximum relevance" (not limited to embodiments of this particular range, or even necessarily limited to normalized "relative" values). For example, to avoid bias, the quality metric values ​​of the components used as the synthetic quality metric can be normalized, for example, to the interval [0, 1], by dividing each metric value by a known maximum value. For example, a quality metric indicating the number of grid aperture trajectory intersections can be divided by the total number of grid apertures (e.g., 169 for a typical 13×13 high-dose-rate brachytherapy grid template). A quality metric indicating the total (summed) length of line segments can be divided by the boundary dimensions of the target volume(s), such as the maximum length of the lesion along the insertion direction of the interventional tool. The quality metric indicating the distance from the closest trajectory to the center of the target volume can be normalized by the grid diagonal length or by the boundary dimensions of the target volumes(s) (e.g., the maximum diameter or radius in a plane parallel to the grid template). Therefore, the selector can choose the grid position / orientation that achieves the maximum composite metric / target value and can output that selected configuration.

[0121] Device 1 may include output 8 for outputting the position and / or orientation selected by position selector 6, for example, for further evaluation and / or use by user through user interface 7.

[0122] Device 1 may include a grid template alignment evaluator 9 for receiving a position signal indicating the position and / or orientation of a physical grid template relative to the patient's body, and for providing a feedback signal indicating the position and / or orientation selected by the position selector 6.

[0123] For example, a grid template alignment evaluator can visualize position signals and selected positions on a display device (e.g., in user interface 7), allowing the user to position / orient the physical grid template to achieve alignment with the selected position / orientation. Therefore, real-time visual guidance can be provided to aid in optimal manual grid positioning. For example, both the outline of the physical grid template based on the received position signal and the outline of the grid template corresponding to the selected position and / or orientation can be displayed, for example, using different line styles, colors, or blinking attributes (e.g., one can be shown as a permanent shape, i.e., continuous display, while the other can be shown as a blinking shape, i.e., intermittent display). For example, the selected position can be represented by a blinking outline and / or by a dashed outline. For example, the outline of the current (physical) grid position can be displayed in a different color than the optimal (selected) grid position. Figure 4In the example shown, the optimal grid position is represented by dashed line 41, while the current manual position is shown by solid line 42. When two contours coincide, such as when alignment has been achieved, this can be indicated by appropriate changes in the presented image. For example, as... Figure 4 As shown on the right, the color of solid line 42 can change from, for example, red (left image) to green (right image).

[0124] Alternatively or additionally, the feedback signal may include an audio signal to indicate a measurement of the difference between the selected location and the physical location. For example, the frequency of the tone or the frequency of the audio pulse may increase or decrease as a function of the distance between the selected location and the physical location (and / or take into account differences in orientation). Thus, for example, an audio pulse with an increasing frequency could be used to indicate that the location is closer to the optimal position.

[0125] Alternatively or additionally, the feedback signal may include actuator signals for controlling one or more actuators adapted for positioning the physical grid template. Thus, the device can automatically control the position of the physical grid template to position it at a selected location / orientation.

[0126] Position signals can be received from tracking sensor 53, such as an electromagnetic (EM) tracking sensor, which is integrated into or attached to the grid template, or to a carrier mechanism (e.g., a stepper device) for positioning the grid template. For example, grid template 51 can be mounted on translation and / or rotation stages 50, 52, 60, such as... Figure 5 and Figure 6 The ultrasonic stepper device 50 shown can provide fine control over the translation and tilting of the grid template, such as... Figure 7 As shown. The stage 60 (and possibly the rotary table 52) allows for coarse positioning and rotation of the ultrasonic stepper device 50, thereby enabling a large number of degrees of freedom for positioning and orienting the grid template, while allowing for precise movement, at least in the degrees of freedom provided by the ultrasonic stepper device.

[0127] While position signals can be received from tracking sensor 53 (e.g., an EM tracking sensor), embodiments may also provide different means of determining the actual position and / or orientation of the physical grid template. For example, the grid template may be detected in a real-time imaging stream, such as fluoroscopy, optical imaging, ultrasound imaging, magnetic resonance imaging, or other forms that allow image information to be captured at a sufficiently high frequency (e.g., at least 5 images per minute, preferably at least 20 images per minute, more preferably at least 1 image per second, and ideally at least 20 images per second).

[0128] In a second aspect, the present invention relates to a clinical workstation 30 comprising the device 1 described above. The clinical workstation can be adapted for presenting visual information, such as an imaging visualization workstation. The workstation may include one or more graphical display devices, such as a monitor, multiple user interface devices, such as a keyboard and / or mouse and / or other human interface devices known in the art, and a processor. The workstation may be implemented by a computer, smartphone, tablet computer, web server computer, and / or a combination thereof. Such a clinical workstation can be adapted to or integrated into radiology suites, biopsy laboratory suites, process room suites, radiotherapy planning and / or execution systems, etc.

[0129] In addition to device 1 and / or clinical workstation 30, embodiments may also include tracking sensor 53 and / or grid template 51 and / or stepper device 50, for example, as a component kit. Embodiments may also include at least one interventional tool, such as a needle, catheter, ablation probe, needle loaded with one or more brachytherapy seeds, etc., adapted for use with the grid template, for example having dimensions that, for example, preferably fit into orifices configured in the grid template in a sufficiently tight but slidable manner.

[0130] In a third aspect, the present invention relates to a computer-implemented method for determining the position and / or orientation of a grid template relative to a human or animal body during a medical intervention, wherein the grid template includes a plurality of holes defining corresponding grid hole trajectories, and wherein the grid template is adapted to support and guide at least one interventional tool along such grid hole trajectories when inserted into the body through at least one of the holes during the intervention.

[0131] Figure 8 An exemplary computer-implemented method 100 according to an embodiment of the present invention is shown.

[0132] The computer-implemented method 100 includes receiving and / or processing data 101 representing at least one target space volume in the body, and optionally also receiving and / or processing data representing at least one risk space volume in the body. For example, such data may include at least one segmented medical image, wherein at least one target space volume and / or said at least one risk space volume in the body is represented by a corresponding segmentation label; and / or at least one surface mesh and / or parametric space descriptor for at least one target space volume and / or at least one risk space volume in the body; and / or at least one medical image. For example, processing the data may include segmenting at least one medical image to determine at least one target space volume and / or at least one risk space volume in the body (even though, according to embodiments of the invention, such segmentation may alternatively be received from an external source). The processing may include determining the segmented surface mesh, or such surface mesh (or alternative descriptor) may be received from an external source.

[0133] Method 100 includes generating a plurality of candidate positions and / or orientations of a 102 grid template relative to at least one target space volume in the body.

[0134] Method 100 includes: for each candidate location and / or orientation, determining the spatial relationship between each grid aperture trajectory of the 103 grid template, when positioned according to the candidate location and / or orientation, and optionally also determining the spatial relationship with the at least one risk volume. For example, the intersection between each grid aperture trajectory and the at least one target volume (or each of the at least one target volume) may be determined.

[0135] The method includes: for each of a plurality of candidate locations and / or orientations, calculating at least one quality metric representing the fitness of the candidate locations for the raster template of the intervention process.

[0136] The calculation 104 includes calculating at least one quality metric by considering values ​​indicating the geometric overlap and / or proximity of a grid aperture trajectory based on a determined spatial relationship relative to at least one target volume. When constrained by the determined spatial relationship, the calculation of the at least one quality metric may consider values ​​indicating a measure of the therapeutic effect of a medical intervention procedure.

[0137] For example, at least one quality metric can be calculated by considering at least a first value, which indicates the degree of intersection between the grid aperture trajectory and at least one target volume for a candidate location and / or orientation. The first value may include the total number of grid aperture trajectories intersecting with at least one target volume, and / or the total length of the segments corresponding to the intersection, and / or other statistical measures of the average or central tendency of the lengths of the segments corresponding to the intersection.

[0138] The calculation of at least one quality metric may also consider a second value indicating the degree of intersection between the grid aperture trajectory for a candidate location and / or orientation and at least one risk volume. The second value may include the total number of grid aperture trajectories intersecting with at least one risk volume, and / or the total length of the line segments corresponding to the intersections with at least one risk volume, and / or other statistical measures of the average length or central tendency of the line segments corresponding to the intersections with at least one risk volume.

[0139] The calculation of at least one quality metric may also take into account a third value, wherein the third value indicates the minimum distance from the grid aperture trajectory to the center of the at least one target volume, or the minimum distance to the center of at least one of the at least one target volumes.

[0140] Calculating at least one quality metric 104 may include calculating multiple metrics, such as one or more “first” values ​​(e.g., the number of crosses, total length, and / or average), and / or one or more “second” values ​​(e.g., the number of crosses, total length, and / or average) and / or third values, and combining the multiple quality metrics into a composite quality metric based on a weighted sum.

[0141] Method 100 includes: selecting 105 positions and / or orientations from a plurality of candidate positions and / or orientations based on at least one quality metric, such as selecting positions and / or orientations that reach the extreme values ​​of one or more quality metrics and / or a synthetic quality metric from a plurality of candidate positions and / or orientations. Selection 105 may also include a stepwise selection based on a priority order of the plurality of quality metrics evaluated in a predetermined or configurable order (e.g., a lexicographical ordering method as described above).

[0142] Therefore, a direct search can be performed on a finite discrete set of candidate grid locations and / or orientations to find the (substantially) optimal location and / or orientation that maximizes the intersection of the grid aperture trajectory with (multiple) target lesions, possibly taking into account tissues / organs at risk and / or preferences that may take into account more symmetrical or at least more centrally distributed grid aperture trajectories than (multiple) target lesions.

[0143] The method may also include receiving a position signal 107 indicating the physical location and / or orientation of the physical grid template.

[0144] The method may include providing 108 feedback signals that indicate a selected location and / or orientation, and / or physical location and / or orientation, and / or the relative location and / or orientation between the physical location and / or orientation and the selected location and / or orientation.

[0145] For example, providing 108 feedback signals may include simultaneously visualizing the physical location and / or orientation, as well as the selected location and / or orientation, using a user interface. For instance, during manual positioning of the guide grid, the current physical location and the determined “optimal” location of the guide grid can be visualized in real-time on a suitable graphical user interface (GUI) to guide the user. For example, the calculated optimal grid location can be visualized in real-time on the GUI, such as as a flashing square (not limited to this), to guide clinical experts during manual positioning of the guide grid template, with its location indicated in real-time, preferably using different display styles to allow easy differentiation between the two shapes.

[0146] For example, providing 108 feedback signals may include generating an audio signal to indicate a measurement of the deviation between the selected location and / or orientation and the physical location and / or orientation.

[0147] For example, providing a 108 feedback signal may include generating an actuator signal for controlling one or more actuators adapted for positioning the physical grid template.

[0148] The method may also include using selected location and / or orientation as input, for example, as predetermined parameters of a planning algorithm, to perform forward or reverse treatment planning for the intervention procedure. Such planning algorithms are well known in the art and therefore will not be discussed in more detail in this disclosure. Similarly, a workstation according to an embodiment of the second aspect of the invention may include a treatment planning system for performing the forward or reverse treatment planning.

[0149] Embodiments of the present invention may also relate to a method comprising the steps of: obtaining such a (physical) grid template, obtaining data representing at least one target space volume in the body using medical imaging techniques, and performing the computer-implemented method as described above. Thus, the location / orientation of the grid template used can be determined during medical interventions, such as lesion treatment, biopsy, or another medical intervention performed by specifically inserting an interventional tool into a target space volume within the body. As is known in the art, the grid template, such as a guide grid frame or treatment grid, can be a rigid or flexible grid template. The grid template can be radially opaque (but is not limited thereto). The grid template includes a plurality of holes, i.e., through-holes, located at different locations on the grid template.

[0150] For example, this method may include imaging the patient's body to provide the data.

[0151] For example, this method may also include determining the physical location and / or orientation of the physical grid template, for example, by using a position sensor to provide a position signal.

[0152] This method may also include braking the actuator based on a feedback signal to position the grid template, or it may include manually positioning the grid template by using a feedback signal for guidance (e.g., audio / visual cues).

[0153] In view of the foregoing description relating to the method according to embodiments of the present invention, other features of the device according to embodiments of the present invention or details of the foregoing features will be clear, and vice versa.

[0154] In a fourth aspect, the present invention relates to a computer program product for executing, when on a suitable processor, a computer-implemented method according to an embodiment of the invention.

Claims

1. A processing device (1) for determining the position and / or orientation of a grid template relative to a human or animal body during a medical intervention, wherein the grid template includes a plurality of holes defining corresponding grid hole tracks, and wherein the grid template is adapted to support and guide at least one interventional tool along the grid hole tracks when inserted into the body through at least one of the plurality of holes during the intervention, the processing device comprising: - Anatomical spatial information processing unit (2), for receiving and / or processing data representing at least one target space volume in the body; - A grid position sampler (4) for generating multiple candidate positions and / or orientations of the grid template relative to the at least one target space volume in the body; - Quality calculator (5), for: calculating at least one quality metric representing the fitness of the candidate position of the grid template for the intervention process for each of the plurality of candidate positions and / or orientations, and - A location selector (6) for selecting a location and / or orientation from the plurality of candidate locations and / or orientations based on the at least one quality metric. The mass calculator (5) is adapted to: for each candidate location and / or orientation, determine the spatial relationship between the trajectory of each grid hole of the grid template, when positioned according to the candidate location and / or orientation, and the at least one target volume. The at least one quality metric includes a value indicating the therapeutic effect of the medical intervention procedure when constrained by the determined spatial relationship, the therapeutic effect metric representing the radiation dose or ablation effect received in the at least one target space volume when at least one radiation source or at least one ablation device is positioned along the grid aperture trajectory.

2. The device according to claim 1, wherein the at least one quality metric further comprises: The value indicates the geometric overlap and / or proximity of the grid aperture trajectory relative to the at least one target volume, based on the determined spatial relationship.

3. The device according to claim 1 or 2, wherein the mass calculator (5) is adapted to: determine the spatial relationship by determining the intersection of each grid hole trajectory of the grid template with the at least one target volume when positioned according to the candidate position and / or orientation for each candidate position and / or orientation, and to: calculate the at least one mass metric for each candidate position and / or orientation by at least considering a first value indicating the degree of intersection between the grid hole trajectory for the candidate position and / or orientation and the at least one target volume.

4. The device according to claim 3, wherein the first value includes: The total number of grid aperture trajectories intersecting with the at least one target volume, and / or the total length of the intersecting line segments, and / or the average or median of the lengths of the intersecting line segments.

5. The device according to claim 3, wherein the anatomical spatial information processing unit (2) is further adapted to receive and / or process data representing at least one risk space volume in the body. The quality calculator (5) is adapted to: for each candidate location and / or orientation, determine the intersection of each grid hole trajectory of the grid template with the at least one risk volume when positioned according to the candidate location and / or orientation. The quality calculator is adapted to: calculate the at least one quality metric for each candidate location and / or orientation by considering at least the first and second values, the second value indicating the degree of intersection between the grid aperture trajectory for the candidate location and / or orientation and the at least one risk volume.

6. The device of claim 5, wherein the second value comprises: The total number of grid hole trajectories intersecting the at least one risk volume, and / or the average or median of the lengths of the line segments intersecting the at least one risk volume.

7. The device of claim 3, wherein the mass calculator (5) is adapted to: calculate the at least one mass metric for each candidate location and / or orientation by taking into account at least the first value and the third value, wherein the third value indicates the minimum distance from the grid aperture trajectory to the center of the at least one target volume.

8. The device of claim 3, wherein the mass calculator (5) is adapted to: calculate the at least one mass metric for each candidate location and / or orientation by taking into account at least the first value and the third value, wherein the third value indicates the minimum distance from the grid aperture trajectory to at least one center of the at least one target volume.

9. The device according to claim 3, wherein the at least one quality metric is a plurality of quality metrics, wherein the quality calculator (5) is adapted to combine the plurality of quality metrics into a synthetic quality metric according to a weighted sum, and wherein the position selector (6) is adapted to select from the plurality of candidate positions and / or orientations an extreme value of the synthetic quality metric.

10. The device according to any one of claims 1, 2 and 4-9, wherein the at least one quality metric is a plurality of quality metrics, wherein the position selector (6) is adapted to select a first subset of the plurality of candidate positions and / or orientations based on a first quality metric among the plurality of quality metrics, and to select at least a second subset of the first subset based on a second quality metric among the plurality of quality metrics that is different from the first quality metric.

11. The device according to any one of claims 1, 2 and 4-9, wherein the grid position sampler (4) is adapted to generate the plurality of candidate positions and / or orientations by translating and / or rotating the position and / or orientation representation of the grid template over a plurality of different translation and / or rotation steps.

12. The device according to any one of claims 1, 2 and 4-9, comprising a grid template alignment evaluator (9) for receiving a position signal indicating the physical position and / or orientation of a physical grid template, and for providing a feedback signal indicating the position and / or orientation selected by the position selector (6), and / or indicating the relative position and / or orientation between the physical position and / or orientation and the selected position and / or orientation.

13. The device of claim 12, wherein the grid template alignment evaluator (9) is adapted to: simultaneously visualize the physical location and / or orientation and the selected location and / or orientation using a user interface (7).

14. A computer program product for implementing, when executed on a processor, a computer-implemented method (100) for determining the position and / or orientation of a grid template relative to a human or animal body during a medical intervention, wherein the grid template includes a plurality of holes defining corresponding grid hole tracks, and wherein the grid template is adapted to support and guide at least one interventional tool along the grid hole tracks when inserted into the body through at least one of the plurality of holes during the intervention, the method comprising: - Receive and / or process (101) data representing at least one target space volume in the body, - Generate (102) multiple candidate positions and / or orientations of the grid template relative to the at least one target space volume in the body. - For each candidate location and / or orientation, determine the spatial relationship between (103) each grid hole trajectory of the grid template and the at least one target volume when positioned according to the candidate location and / or orientation. - For each of the plurality of candidate locations and / or orientations, by at least considering values ​​indicating a measure of therapeutic effect of the medical intervention when constrained by the determined spatial relationships, calculate (104) at least one quality metric representing the suitability of the candidate location of the grid template for the intervention, the therapeutic effect measure representing the radiation dose or ablation effect received in the at least one target space volume when at least one radiation source or at least one ablation device is positioned along the grid aperture trajectory, and - Select (105) positions and / or orientations from the plurality of candidate positions and / or orientations based on the at least one quality metric.

Images